Two questions for you experts:

1. In the midst of a very tedious brake job we have managed to strip a couple of the allen bolts that connect the front brake rotor and hub on our '82 240D. The guys at Bap Geon (our local import auto parts store) told us it would be sufficient to use 2-3 bolts instead of the original 5, as long as the bolts were symmetrically spaced. Is this the case? Have any of you ever used less than 5 allen bolts?

2. If using less than 5 bolts is insufficient, does anyone in the Houston area have any spare bolts that would work?

Thank You!

Using less than the required 5 bolts is asking for big trouble. Don't do it!
Aside from the out-of-balance issue, you also have to take into consideration that wheel hubs are major stress points.

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Don't Chrome them; polish them

I would go to the dealer for the correct allen bolts.

Think about it with two bolts of the five missing the percentage of intended strength by the manufacturer is greatly comprimised. As I read you post I wondered if you meant the holes in the hub were damaged as well. Not just a bolt problem.

How do you symmetrically space fewer than 5 bolts in a 5 bolt pattern???

The SF Bay Area is about as expensive a place for MB parts as there is. A W123 rotor-to-hub bolt cost $4.80 (plus tax) at Autobahn Motors in Redwood City within the last 10 days.

Sixto
87 300D

They gave you bad advice. You would think being in the business they would be able to tell you another source to buy from if they do not have the part/s themselves. If there is no Mercedes dealer near buy you might try NAPA. But if you do not know the thread size bring the bolt samples with you.

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84 300D, 82 Volvo 244Gl Diesel

I actually did this once. I talked myself into believing that the wheel lugs would hold on the rotor like a rear wheel does. Obviously it does not. The disc broke loose from the center of itself. It was on my 74 240d that one of my kids was driving at the time. Fortunately when it happened they were not going very fast and nothing bad occurred except I had to buy another new rotor.

Its a very dangerous thing because the wheel will lock up, or at least it did in our case. It would be bad at 40 or 60 mph.

Wait til you can get your hands on some proper bolts.

Tom W

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

Thanks for all of your speedy replies. Our suspicions are confirmed about using fewer than 5 bolts. T Walgamuth - thank you for the firsthand anecdote. We will definitely be finding replacement bolts.

You should drive your car slowly to a welding shop and remove the wheel and have them weld on the broken stud. Getting the broken stud cherry red and letting it cool, will shrink the bolt, and it can then be removed by haviing them weld a nut to the broken stud. The part needs to cool by itself to shrink. Do not quench the part with water or oil or anything else trying to hasten the process. You'll just defeat yourself in the task.
You can position a nut over the broken stud and weld through the hole in the nut to the stud.

When he said he stripped tha Allen bolts I assumed that he striped the heads of the Allen bolts not Sheared them off. So I assumed that they managed to remove the stripped Allen bolts and that only a source of the bolts is needed to complete the job.
I like to use heat to loosen things too but when you get something too hot it alters the structure of the metal. Heating steele cherry read that has any amount of carbon beyond what mild steel has will change the hardening and tempering of the metal. Heating gray cast iron cherry red can change it to white cast iron which is very hard and brittle.

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84 300D, 82 Volvo 244Gl Diesel

I've had great success removing broken bolts and studs using left hand drill bits. The combination of heat from drilling and the left rotation means the broken piece is usually out before I have enough depth to insert an extractor.

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Charles
1983 300D, bought new, 215k+ miles, donated to Purple Hearts veterans charity but I have parts for sale: http://www.peachparts.com/shopforum/showthread.php?t=296386

I was reading the manual for my 300D concerning the Allen Bolts that hold the rotor on. The manual relates that they are "Self-locking Hex Socket Bolts". This sounds to me like you will need to get them at the Dealer or a Junk Yard as you are unlikely to find any self locking Metric Allen Bolts at a regular parts place.
See page 2 of 4 and item #9 text and pic.
http://www.pauldrayton.com/uploadfiles/merc/Service/W123/w123CD2/Program/Chassis/42-220.pdf

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84 300D, 82 Volvo 244Gl Diesel

Some Locktite threadlocker will probably help for the time being in case he found some non-MB-dealer bolts.

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'85 300D Turbo - CA Version

That's it exactly. And for the record, it took a MAPP gas torch, a good air hammer wrench, a 3/4" ratchet designed for 18-wheelers, and about three days of soaking.

F@*%$&# Loctite.

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We did find one through the dealership, but there's a 10-day wait on it.
So much for getting it back on the road this weekend.

Thanks again for your help, everyone.

Haha! No wonder the "head of the allen bolt" stripped! A 3/4" rachet designed for 18 wheelers and...let me guess....a wrong sized(prob'ly non-metric) or cheapo allen socket.....

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'85 300D Turbo - CA Version